Fractures of the hip and wrist are a common, costly and preventable threat to the health and survival of the elderly. A better understanding of the risk factors for hip and Colles' fractures will add to our knowledge about their etiology, and help focus research and preventative efforts on those who are at greatest risk. We propose to characterize risk factors for hip and Colles' fractures in a multicenter prospective study of 9,600 elderly women followed quarterly for an average of 3.5 years. Our cohort will be a population-based sample of non-black women aged 65 or greater who are screened from 1986 thru 1988 at clinical centers in Pittsburgh, Portland, Maryland and Minneapolis. At the baseline exam, we will measure a large set of potential historical and clinical predictors of fractures. We will also use single-photon absorptiometry of the radius and x-ray the hand, spine and hips to determine whether simple radiographic measurements can identify those with the greatest risk of fracture. We will also freeze serum from all participants at the outset and test the stability of hormone measurements on a subsample after storage at -l96 degrees C for several years; measurements that are shown to be stable will be the subject of a future study of the hormonal differences between women in our cohort who suffer fractures and those who do not. We conservatively estimate that 165 hip and 150 Colles' fractures will occur, yielding a power of .90 to detect risk ratios of less than 2.0 common risk factors. Our prospective design will yield more information with fewer potential biases than previous (retrospective) studies on this topic, and our nested-case control analyses will minimize the costs of the expensive endocrinologic and radiologic measurements. The study cohort, and its bank of sera, x-rays and clinical data will be an excellent resource for future studies of osteoporosis, fractures and other diseases of the elderly. The results of our study will guide clinical and public health efforts to prevent these fractures.